共查询到20条相似文献,搜索用时 15 毫秒
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A. D. Ivakhnov T. E. Skrebets K. G. Bogolitsyn 《Russian Journal of Physical Chemistry B, Focus on Physics》2013,7(7):885-888
The possibility of cellulose diacetate production by direct acetylation of sulfite pulp with acetic anhydride in supercritical carbon dioxide (SC CO2) is demonstrated. Optimum acetic anhydride to cellulose ratio and parameters of SC CO2 are selected. 相似文献
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 1, pp. 108–112, January, 1991. 相似文献
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The topology of the surface of thin films obtained from cellulose triacetate solutions has been studied using electron microscopy.
The domain structure of the physical network of macromolecules (percolation cluster) with the maximum size L ≈ 30 nm of regions with a local orientational order has been established. With an increase in the volume fraction Ω of the
cluster to the critical value Ω = 0.91, repacking of domains takes place, which is connected with a decrease in the parameter
Ω, L doubling bifurcation of the size L, and formation of regions of long-range orientational order: the mesophase of the polymer. 相似文献
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Modeling cochlear dynamics: interrelation between cochlea mechanics and psychoacoustics 总被引:1,自引:0,他引:1
A model of the cochlea was used to bridge the gap between model approaches commonly used to investigate phenomena related to otoacoustic emissions and more filter-based model approaches often used in psychoacoustics. In the present study, a nonlinear and active one-dimensional transmission line model was developed that accounts for several aspects of physiological data with a single fixed parameter set. The model shows plausible excitation patterns and an input-output function similar to the linear-compressive-linear function as hypothesized in psychoacoustics. The model shows realistic results in a two-tone suppression paradigm and a plausible growth function of the 2f(1)-f(2) component of distortion product otoacoustic emissions. Finestructure was found in simulated stimulus-frequency otoacoustic emissions (SFOAE) with realistic levels and rapid phase rotation. A plausible "threshold in quiet" including finestructure and spontaneous otoacoustic emissions (SOAE) could be simulated. It is further shown that psychoacoustical data of modulation detection near threshold can be explained by the mechanical dynamics of the modeled healthy cochlea. It is discussed that such a model can be used to investigate the representation of acoustic signals in healthy and impaired cochleae at this early stage of the auditory pathway for both, physiological as well as psychoacoustical paradigms. 相似文献
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Xing-jia Guo Kui Jing Chuang Guo Yu-chun Jiang Jiang Tong Xiao-wei Han 《Journal of luminescence》2010,130(12):2281-2287
The mutual interaction of oxybutynin hydrochloride (OB) with bovine serum albumin (BSA) was investigated by fluorescence, UV–vis absorption, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopies under simulative physiological conditions. The results of fluorescence titration revealed that OB could quench the intrinsic fluorescence of BSA by static quenching and there was a single class of binding sites on BSA for this drug. The thermodynamic parameters ΔH, ΔS, and ΔG calculated at different temperatures indicated that hydrogen bonds and van der Waals interactions were the dominant intermolecular forces in stabilizing the OB–BSA complexes. According to the theory of Förster’s non-radiation energy transfer, the binding distance r between OB and BSA was evaluated to be 3.27 nm. The displacement experiments confirmed that OB could bind to site I of BSA. The FT-IR and CD spectra showed that the binding of OB to BSA induced conformational changes in BSA. 相似文献